diff --git a/server/modules/protocol/MySQL/mysql_common.cc b/server/modules/protocol/MySQL/mysql_common.cc
index 648ce60bc..4efded961 100644
--- a/server/modules/protocol/MySQL/mysql_common.cc
+++ b/server/modules/protocol/MySQL/mysql_common.cc
@@ -1299,8 +1299,8 @@ bool mxs_mysql_extract_ps_response(GWBUF* buffer, MXS_PS_RESPONSE* out)
 {
     bool rval = false;
     uint8_t id[MYSQL_PS_ID_SIZE];
-    uint8_t cols[MYSQL_PS_ID_SIZE];
-    uint8_t params[MYSQL_PS_ID_SIZE];
+    uint8_t cols[MYSQL_PS_COLS_SIZE];
+    uint8_t params[MYSQL_PS_PARAMS_SIZE];
     uint8_t warnings[MYSQL_PS_WARN_SIZE];
 
     if (gwbuf_copy_data(buffer, MYSQL_PS_ID_OFFSET, sizeof(id), id) == sizeof(id)